JP6457985B2 - Medical knife - Google Patents

Description

  The present invention relates to a medical knife capable of realizing an incision having high self-closing property in ophthalmic surgery.

  In ophthalmic surgery, it is preferable to form a highly self-closing incision when a medical knife is inserted into a spherical eyeball and an incision is made between the cornea or cornea and sclera. An incision with high self-closing property is a so-called Fraun incision having a gently curved shape that is convex toward the center when the eyeball is viewed from the front.

  As a medical knife used in ophthalmic surgery, a bevel-up type whose cross-sectional shape is formed in a trapezoidal shape with the surface connecting the edges as the bottom surface, a bi-layer formed in an abacus bead shape in which the lines connecting the edges are at approximately intermediate positions A bevel type and the like are provided and are used selectively.

  In the case of a bevel-up type knife, the force generated by the intraocular pressure and the incision resistance acting at the time of incision differs between the upper surface and the lower surface, and the force acting downward as the incision progresses increases and shifts toward the bottom as a whole. It has the characteristics. This knife can form an incision with a relatively high self-closing property. In addition, in the case of a bevel-type knife, the forces acting on the upper surface and the lower surface are substantially equal during incision, and the insertion direction is linear, but the self-closing property of the formed incision is very high. There is no.

  Development of a medical knife capable of forming a more preferable incision is always required, and the medical knife described in Patent Document 1 has been proposed in response to this request. This medical knife was developed for the purpose of forming a highly self-closing incision, with the sharp tip formed at the tip of the blade as the apex and the edge up to the maximum width of the rhombus Is formed.

  Then, a first inclined surface inclined in the thickness direction from the edge toward the inner side with the surface including the edge as a boundary, and a second inclined surface continuous with the first inclined surface are formed, and the uppermost side is formed. Is formed as an upper plane. Further, a lower inclined surface inclined in the thickness direction from the edge toward the inner side of the blade portion and a plane continuous to the lower inclined surface are formed on the lower side with the surface including the edge as a boundary. In particular, the thickness on the upper surface side is set to be in the range of 75% to 93% of the total thickness in the blade portion with the surface including the edge as a boundary.

  In the medical knife described above, when incising between the cornea or the cornea and the sclera, the force acting on the upper surface side is caused by the intraocular pressure and the incision resistance acting when the tip is inserted into the cornea on the spherical surface. The difference is small, although it is greater than the force acting on. For this reason, the incision seen from the insertion direction of the medical knife has a gentle curve that is convex upward. In addition, the incision seen from the front of the eyeball is a more gentle curve that is convex toward the center of the eyeball. Such an incision is preferable because of its high self-closing property.

Japanese Patent No. 4269299 (Japanese Patent Laid-Open No. 2001-238890)

  With the medical knife described in Patent Document 1, an incision with high self-closing property can be formed during ophthalmic surgery. However, there is a demand for the development of a medical knife that can always form a better incision.

  An object of the present invention is to provide a medical knife capable of forming an incision having a higher self-closing property.

In order to solve the above problems, a medical knife according to the present invention is a medical knife in which an edge is formed along the outer periphery of the blade portion, and the planar projection shape of the blade portion is formed at the tip portion of the blade portion. The outer periphery of the blade portion is formed in a substantially triangular shape including a tip portion including the tip and the vicinity of the tip, the widest maximum width portion, and a side surface portion formed between the tip portion and the maximum width portion. A front side slope that constitutes an edge on the front side and a back side slope that constitutes an edge on the back side are respectively formed with a virtual plane including an edge formed along the boundary as a boundary. The ratio of the angle formed between the virtual surface and the back surface side slope to the angle formed between the virtual surface and the surface side slope is the virtual surface and the back surface relative to the angle formed between the front surface side slope in the side surface portion. Be larger than the ratio of the angle with the side slope. It is an butterfly.

In the medical knife, it is preferable that the virtual surface is a boundary, and the thickness of the front surface side of the virtual surface is larger than the thickness of the back surface side.

  In any one of the medical knives described above, a ratio of an angle formed by the virtual surface and the back-side inclined surface to an angle formed by the virtual surface and the front-side inclined surface is substantially constant at the side surface portion. It is preferable.

  The medical knife (hereinafter simply referred to as “knife”) according to the present invention can form an incision that exhibits high self-closing properties.

  With the virtual plane including the edge formed along the outer periphery of the blade part as a boundary, the back-side slope and the virtual plane formed on the back side with respect to the angle formed by the front-side slope and the virtual plane formed on the front side The ratio of the angle formed is greater at the tip than at the side. For this reason, the difference in force generated from the front surface side to the back surface side due to intraocular pressure or incision resistance acting when the eyeball is incised is smaller at the tip portion and larger at the side portion.

  Accordingly, when the eyeball is incised, the force for lowering the knife to the back side is small at the tip, and the force for moving straight is increased, so that a curved incision with a small curvature can be formed. In addition, a force for lowering the knife to the back side is greater at the side surface than at the tip, and a curved incision with a large curvature can be formed. In this way, a highly self-closing incision can be formed.

  In particular, when the imaginary line including the edge is used as a boundary and the thickness on the front surface side of the virtual surface is larger than the thickness on the back surface side, the force acting on the front surface side and the back surface side when the eyeball is incised. The difference with force can be reduced.

  In addition, the ratio of the angle formed by the virtual surface and the back surface side slope to the angle formed by the virtual surface and the front surface side slope is substantially constant at the side surface, so that when the knife is inserted into the eyeball, the side surface portion The force acting so as to lower the back surface side can be set to a substantially constant value. For this reason, the doctor can proceed with the incision operation in a stable state.

It is a figure which shows the surface and back surface of the knife which concern on 1st Example. It is a fragmentary sectional view of FIG. It is an enlarged view of an edge part. It is a figure which shows the surface and back surface of the knife which concern on 2nd Example.

  Hereinafter, the knife according to the present invention will be described. The knife according to the present invention makes it possible to form an incision having high self-closing properties when an eyeball is incised.

  The knife according to the present invention has a function of piercing the eyeball to form an initial incision, incising and expanding the initial incision as a starting point. Then, when performing an operation to embed a lens in the eyeball, insert a chip of an ultrasonic emulsification suction device for sucking the crystalline lens from the eyeball, or cut a length that allows insertion of a lens to be embedded in the eyeball. It forms a wound.

  It does not specifically limit as a material which comprises the knife which concerns on this invention, Steels, such as stainless steel and carbon steel, can be used. However, considering the antirust surface and the ease of processing, stainless steel is preferable, and austenitic stainless steel is particularly preferable.

  When using austenitic stainless steel as a raw material, in order to increase the hardness of the raw material, cold plastic working is performed at a predetermined processing rate to stretch the structure into a fiber shape, and the fiber-like structure is maintained and pressed. It is preferable to perform processing, polishing, and other necessary processing.

  In the knife according to the present invention, the planar shape of the blade portion includes a sharp tip, a tip including the vicinity of the tip, a maximum width, and a side portion formed between the tip and the maximum width. It is formed in a roughly diamond shape. And the edge (cutting blade) is formed in the outer peripheral part from a point to the maximum width part. For this reason, it is possible to form an incision corresponding to the dimension of the maximum width portion by inserting the tip into the eyeball and moving it straight. In addition, it is possible to form an incision having a desired width regardless of the size of the maximum width portion by inserting a tip into the eyeball and moving it in the left-right direction.

  In the knife according to the present invention, the vicinity of the apex constituting the tip is assumed to be a triangle having the apex at the apex and the line connecting the edges of the maximum width portion as the base, and a perpendicular (axis line from the apex to the base) The range of up to ½, preferably up to ¼. If the length of the vicinity of the apex, including the apex that forms the tip, exceeds 1/2 of the length of the perpendicular from the apex to the base, an incision similar to a conventional beveled knife incision is formed. It is not preferable. In addition, when the length is about 1/30 or less smaller than ¼ of the length of the perpendicular line from the apex to the base, the range in which the straightness of the knife that occurs when incision starts can be reduced, and high self-incision property An incision with no can be formed.

  Further, the knife according to the present invention assumes a virtual surface including a pair of edges formed along the outer periphery of the blade portion with the apex as the apex, and a surface-side inclined surface is formed on the surface side with this virtual surface as a boundary. A back side slope is formed on the side. The ratio of the angle between the imaginary surface and the back-side slope to the angle between the imaginary surface and the surface-side slope at the tip (the ratio of the angle at the tip) is the surface-side slope at the side. Is larger than the ratio of the angle formed by the imaginary plane and the back-side inclined surface to the angle formed by (the ratio of the angle at the side surface).

  There is no particular limitation on how much the angle ratio at the tip portion is larger than the angle ratio at the side surface portion. When performing ophthalmic surgery, the tip portion exhibits sufficient straightness and the side surface. It is preferable that the ratio is such that a moderate downward force can act on the part. That is, it is preferable to set the ratio so that the tip portion has characteristics of a bevel-type knife and the side portion has bevel-up type characteristics.

  When the ratio of the angle at the tip is larger than the ratio of the angle at the side, the angle formed by the front-side slope with respect to the virtual surface at the tip, and the back-side slope with respect to the virtual surface at the tip This can be achieved by setting the angle to be made, the angle made by the front side slope to the virtual surface at the side surface, and the angle made from the back side slope to the virtual surface at the side surface as independent angles. is there.

  For example, the angle formed by the front surface slope with respect to the virtual surface at the front end portion and the side surface portion is constant, and the angle formed by the rear surface side slope with respect to the virtual surface at the front end portion is set as the back surface side slope with respect to the virtual surface at the side surface portion. It can be realized by setting it larger than the angle formed by Alternatively, the angle formed by the surface side slope with respect to the virtual surface at the front end portion is smaller than the angle formed by the surface side slope with respect to the virtual surface at the side surface portion, and the back surface side with respect to the virtual surface at the tip portion and side surface portion. It can be realized even if the angle formed by the slope is constant.

  Moreover, it is preferable that the thickness on the front surface side is larger than the thickness on the back surface side with the virtual surface as a boundary. There is no particular limitation on how much the thickness on the front side is greater than the thickness on the back side, and when the side part is inserted into the eyeball, the downward force acting acts to form a self-closing incision. It is preferable that the thickness be obtained.

  In the side surface portion, it is preferable that the ratio of the angle formed by the virtual surface and the back surface side slope to the angle formed by the virtual surface and the front surface side slope is substantially constant. In this case, the difference between the force acting on the front surface side and the force acting on the back surface side in the side surface portion is substantially constant. For this reason, the movement dimension in the back surface direction when the unit length is inserted becomes substantially constant, and it becomes possible to form an incision made of a curve having a stable curvature.

  Next, a first embodiment of the knife will be described with reference to FIGS. In the knife according to the present embodiment, the angle formed by the front-side inclined surface with respect to the virtual surface at the front end portion and the side surface portion is constant, and the angle formed between the rear surface-side inclined surface with respect to the virtual surface at the front end portion is the virtual angle at the side surface portion. It is set to be larger than the angle formed by the back side slope with respect to the surface.

  In the drawing, the knife A is configured to have a blade portion 1 and a shank (not shown) continuous with the blade portion 1. A sharp tip 2 is formed on the blade portion 1, and a tip 3 is formed including the tip 2 and the vicinity of the tip 2. A maximum width portion 4 of the blade portion 1 is formed at a position separated from the tip 2, and a portion between the tip portion 3 and the maximum width portion 4 is formed as a side surface portion 5.

  The distance from the tip 2 to the maximum width portion 4, the detailed dimensions such as the width dimension of the maximum width portion 4, and the range of the tip 3 are variously set according to the purpose of the knife A, for example, the specifications of the incision, etc. ing.

  A pair of edges 7 are formed along the outer periphery of the blade portion 1 with the tip 2 as a vertex and reaching the maximum width portion 4. The edge 7 has a function of cutting the living tissue, and the surface-side inclined surface 8 and the back surface formed on the surface side with a virtual surface 7a including a pair of edges 7 formed along the outer periphery of the blade portion 1 as a boundary. It is formed by crossing the back side slope 9 formed on the side. Thus, since the front surface side slope 8 and the back surface side slope 9 jointly form the edge 7, these slopes 8 and 9 are formed as a ground surface with high smoothness.

  A second inclined surface 10 is formed along the surface-side inclined surface 8 formed on the surface side in the blade portion 1, and a boundary line 8 a is formed at the boundary between both the inclined surfaces 8 and 10. Accordingly, the second inclined surface 10 is formed between the surface-side inclined surfaces 8 constituting both edges 7. Since the second inclined surface 10 does not have a function as a cutting edge, it is not necessarily formed by a ground surface having high smoothness, and may be a pressed surface or a rough ground surface.

  A surface side plane 11 is formed between the pair of second slopes 10 along the second slope 10. The surface side plane 11 may also be a pressed surface or a rough ground surface like the second inclined surface 10.

  In the present embodiment, the second inclined surface 10 and the surface side plane 11 are provided, but the second inclined surface 10 and the surface side plane 11 are not indispensable, and a configuration without these is also possible. It is. For example, the front side inclined surface 8 may be extended inside the blade portion 1 and crossed at the center, and the second inclined surface 10 may be extended inside the blade portion 1 and crossed at the center. In this case, the surface to be extended may be a flat surface or a curved surface.

  A back side flat surface 12 is formed continuously between the back side slopes 9 between a pair of back side slopes 9 formed on the back side in the blade portion 1. The back surface side plane 12 is formed as a surface that does not have a function as a cutting edge, like the second inclined surface 10 and the surface side surface 11 described above. For this reason, it is not necessarily a ground surface with high smoothness, and it may be formed as a rough ground surface or a press surface.

  The tip 3 is formed including the tip 2 and the vicinity of the tip 2. The range in the vicinity of the tip 2 is not limited, and is preferably a range in which an incision suitable for exhibiting the self-closing property required for ophthalmic surgery can be formed.

  In the present embodiment, the line connecting the maximum width portions 4 (the CC line in FIG. 1A) is the bottom, and on the perpendicular (axis) passing through the tip 2, about 1 / of the dimension from the tip 2 to the base. A range of 5 is set as the tip 3. However, it is not limited to this range, and it may be longer or shorter.

  As described above, in the present embodiment, the angle formed by the surface side inclined surface 8 with respect to the virtual surface 7a at the tip portion 3 and the side surface portion 5 is constant. The angle formed by the back surface side inclined surface 9 a with respect to the virtual surface 7 a at the front end portion 3 is set larger than the angle formed by the back surface side inclined surface 9 b with respect to the virtual surface 7 a at the side surface portion 5.

  In particular, the transition portion is formed as a smooth curved surface so that it can continuously transition from the back surface side inclined surface 9a constituting the tip portion 3 to the back surface side inclined surface 9b constituting the side surface portion 5.

  Next, the angle formed by the virtual surface 7a and the front surface side inclined surface 8 at the front end portion 3 with the virtual surface 7a at the front end portion 3 and the side surface portion 5 as a boundary, the virtual surface 7a and the rear surface side inclined surface 9 ( The relationship between the angles formed by 9a and 9b) will be described.

  2A is a cross-sectional view taken along the line AA at the distal end portion 3, and FIG. 3A is an enlarged explanatory view of the edge 7. FIG. 2B is a cross-sectional view taken along the line BB in the side surface portion 5, and FIG. 3B is an enlarged explanatory view of the edge 7. 2C is a cross-sectional view taken along the line C-C in the maximum width portion 4, and FIG. 3C is an enlarged explanatory view of the edge 7.

  As shown in the drawing, the edge 7 at the tip 3 crosses the virtual surface 7a at the angle α with the virtual surface 7a as a boundary and the surface-side inclined surface 8 that intersects the virtual surface 7a at the angle β. And a back side inclined surface 9a.

  Further, the edge 7 in the side surface portion 5 has the virtual surface 7a as a boundary, and the front surface side inclined surface 8 intersecting the virtual surface 7a at an angle α and the back surface side inclined surface 9b intersecting the virtual surface 7a at an angle θ. And is composed of. Further, the edge 7 in the maximum width portion 4 has a virtual surface 7a as a boundary, and a front-side slope 8 intersecting the virtual surface 7a at an angle α, and a back-side slope intersecting the virtual surface 7a at an angle θ. 9.

  The values of the angles α, β, and θ are not limited. However, the angle β is set to be larger than the angle θ. That is, the ratio of the angle β formed between the virtual surface 7a and the back-side inclined surface 9a to the angle α formed between the virtual surface 7a and the front-side inclined surface 8 at the edge 7 of the tip 3 is β / α. Further, the ratio of the angle formed between the virtual surface 7a and the back surface side inclined surface 9b to the angle α formed between the virtual surface 7a and the front surface side inclined surface 8 at the edge 7 of the side surface portion 5 is θ / α. Therefore, the ratio β / α at the tip 3 is larger than the ratio θ / α at the side 5.

  Since the ratio β / α is larger than the ratio θ / α, when the eyeball is pierced by the knife A, the difference in force between the front surface side and the back surface side acting on the tip portion 3 is different from the front surface side acting on the side surface portion 5. It becomes smaller than the difference in force on the back side. Therefore, when the knife A is inserted straight into the eyeball in the axial direction, the distal end portion 3 can be incised by being substantially straightly advanced, and the knife A is moved from the distal end portion 3 to the side surface portion 5. Can be incised while moving (lowering) in the direction of the back surface.

  As a result, when the incision formed in the eyeball is viewed from the front, the incision formed by the distal end portion 3 has a gentle curved shape, and the incision formed by the side surface portion 5 has a downward curve with a larger curvature. A Fraun incision can be realized by such an incision.

  In the present inventors, the dimension of the maximum width portion 4 is 2.4 mm, the dimension in the axial direction from the tip 2 to the maximum width 4 is 3.0 mm, and the dimension of the tip 3 is approximately 0. 0 in the axial direction from the tip 2. 5 mm, the dimension of the side surface 5 is approximately 3.0 mm continuously from the tip 3, the angle between the pair of edges 7 having the tip 2 as the apex is approximately 60 degrees, the virtual surface 7 a and the surface at the tip 3 The angle α formed by the side slope 8 is approximately 21.5 degrees, the angle β formed by the virtual surface 7a and the back surface side slope 9a is approximately 11.5 degrees, and the virtual surface 7a and the surface side slope 8 in the side surface portion 5 are set. And a knife having an angle θ between the imaginary surface 7a and the back-side inclined surface 9b of approximately 9.5 degrees was created.

  In the knife, the ratio β / α at the tip 3 is 0.53, and the ratio θ / α at the side 5 is 0.44. Therefore, the ratio β / α at the tip 3 is larger than the ratio θ / α at the side 5.

  When an experiment was performed to form an incision on the pig's eyeball using the knife configured as described above, the incision from the tip 2 to the tip 3 became a gentle curve with a small curvature, and the incision on the side 5 was A curved shape having a larger curvature than that of the incision was obtained. It was concluded that the incision obtained in this experiment was a sufficiently favorable Fraun incision.

  Next, the configuration of the knife A according to the second embodiment will be described with reference to FIG. In the figure, the same portions as those in the first embodiment described above or portions having the same functions are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, a boundary line 9 c is formed at a portion of the back side slope 9 that transitions from the back side slope 9 a constituting the tip 3 to the back side slope 9 b constituting the side face 5. That is, the back surface side inclined surface 9a of the front end portion 3 and the back surface side inclined surface 9b of the side surface portion 5 are not continuously connected but are connected via a clearly formed boundary line 9c. Such back-side inclined surfaces 9a and 9b can be realized by using a grinding material having high rigidity and grinding the knife material in accordance with angles β and θ set in advance. is there.

  As described above, even if the back side slopes 9a and 9b are connected via the boundary line 9c, the piercing property at the time of incision is not affected. It was a small, loosely curved shape, and the side surface portion 5 had a curved shape with a larger curvature than the incision.

  In the present embodiment, the boundary line 9c is formed at a portion of the back side slope 9 corresponding to the tip 3 from the back side slope 9a to the side slope 9b. However, the ratio β / α at the tip 3 is changed to the ratio at the side 5 by changing the angle between the range corresponding to the tip 3 on the front side slope 8 and the range corresponding to the side 5. When it is larger than θ / α, it is a matter of course that the front end portion 3 and the side surface portion 5 on the front surface side inclined surface 8 may be connected by a clear boundary line.

  The knife A according to the present invention can be used when forming an incision with high self-closing property in ophthalmic surgery.

A Knife 1 Blade part 2 Point 3 Tip part 4 Maximum width part 5 Side part 7 Edge 7a Virtual surface 8 Surface side slope 9, 9a, 9b Back side slope 9c Boundary line 10 Second slope 11 Surface side plane 12 Back side plane

Claims (3)

A medical knife having an edge formed along the outer periphery of the blade part,
The planar projection shape of the blade portion was formed between the tip formed at the tip of the blade and the tip including the vicinity of the tip, the widest maximum width, and the tip and the maximum width. Formed in a substantially triangular shape consisting of side portions,
And the imaginary plane including the edge formed along the outer periphery of the blade part is used as a boundary, the front side slope that constitutes the edge on the front side, and the back side slope that constitutes the edge is formed on the back side, respectively.
The ratio of the angle formed by the virtual surface and the back surface side slope to the angle formed by the virtual surface and the surface side slope at the tip portion is relative to the angle formed by the surface side slope at the side surface portion. A medical knife characterized by being larger than a ratio of an angle formed by the virtual surface and the back-side slope. 2. The medical knife according to claim 1, wherein the virtual surface is a boundary, and the thickness of the front surface side of the virtual surface is larger than the thickness of the back surface side.   The ratio of the angle formed by the virtual surface and the back surface-side inclined surface to the angle formed by the virtual surface and the front surface-side inclined surface is substantially constant in the side surface portion. Medical knife.

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